Steven N. Jeffers

Steven N. Jeffers
Clemson University | CU · Department of Plant & Environmental Sciences

About

78
Publications
9,725
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2,552
Citations
Citations since 2016
10 Research Items
912 Citations
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140

Publications

Publications (78)
Article
Full-text available
Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4) is a devastating fungus pathogen that causes Fusarium wilt in both domesticated cotton species, Gossypium hirsutum (Upland) and G. barbadense (Pima). Greenhouse and field-based pathogenicity assays can be a challenge due to non-uniform inoculum levels, the presence of endophytes, and varying envir...
Article
Full-text available
Root-knot nematodes (RKNs), Meloidogyne spp., are some of the most economically important pathogens of cultivated plants. Meloidogyne javanica is one of the most destructive RKN species and is well known for its broad host range and the severe damage it causes to plant roots (Perry et al. 2009). In Feb 2018, four mature dead and dying hybrid lavend...
Article
Investigations of the susceptibility of aquatic plants to species of Phytophthora are limited. Therefore, the objective of this study was to assess the potential susceptibility of six aquatic plant species, frequently used in constructed wetlands or vegetated channels, to infection by five species of Phytophthora commonly found at nurseries in the...
Article
Chrysanthemum (Chrysanthemum × morifolium) plants exhibiting stem and foliage blight were observed in a commercial nursery in eastern Oklahoma in June 2019. Disease symptoms were observed on ~10% of plants during a period of frequent rain and high temperatures (26-36°C). Dark brown lesions girdled the stems of symptomatic plants and leaves were wil...
Article
Full-text available
Constructed wetlands have been used for decades in agricultural settings to remediate nutrients and other agrichemicals from irrigation runoff and drainage; however, little is known about the presence and distribution of Phytophthora species within irrigation runoff water being treated in constructed wetlands. Therefore, we collected plant samples...
Article
The soilborne oomycete Phytophthora cinnamomi-which causes root rot, trunk cankers, and stem lesions on an estimated 5,000 plant species worldwide-is a lethal pathogen of American chestnut (Castanea dentata) as well as many other woody plant species. P. cinnamomi is particularly damaging to chestnut and chinquapin trees (Castanea spp.) in the south...
Article
Full-text available
Restoration of American chestnut (Castanea dentata) depends on combining resistance to both the chestnut blight fungus (Cryphonectria parasitica) and Phytophthora cinnamomi, which causes Phytophthora root rot, in a diverse population of C. dentata. Over a 14-year period (2004 to 2017), survival and root health of American chestnut backcross seedlin...
Article
Root rot (caused by Phytophthora cinnamomi) and chestnut blight (caused by Cryphonectria parasitica) are the two most destructive diseases affecting American chestnut, Castanea dentate. Therefore, breeding for resistance to both pathogens simultaneously is essential before the American chestnut can be restored to its full native range. Using combin...
Article
Recycling irrigation water is a common prac-tice at ornamental plant nurseries for conserving water; however, it poses the risk of sourcing and dispersing waterborne plant pathogens, especially species of Phytophthora. Slow sand filtration is a water treatment process that can remove pathogens from water, but the slow rate of water treatment may li...
Article
Phytophthora nicotianae is a common pathogen of many herbaceous perennial plants, and this pathogen has been found causing disease on garden phlox (Phlox paniculata) in wholesale nurseries in South Carolina for a number of years. However, the relationship between P. nicotianae and garden phlox has not been studied or reported previously. Using Koch...
Article
The occurrence of geranium rust (caused by Puccinia pelargonii-zonalis) in commercial greenhouses can result in unmarketable plants and significant eco-nomic losses. Currently, detection of geranium rust relies solely on scouting for symptoms and signs of the disease. The purpose of this research was to develop a rapid detection assay for P. pelarg...
Article
Full-text available
The goal of this study was to develop a procedure that could be used to evaluate the potential susceptibility of aquatic plants used in con-structed wetlands to species of Phytophthora commonly found in nurseries. V8 agar plugs from actively growing cultures of three or four isolates of Phytophthora cinnamomi, P. citrophthora, P. cryptogea, P. nico...
Article
Full-text available
Gladiolus rust, caused by Uromyces transversalis, is a quarantine significant pathogen in the United States. However, the fungus is endemic to commercial gladiolus-producing areas in Mexico and has been intercepted frequently on gladiolus plants entering the United States for the cut-flower market. The present study assessed 15 fungicide active ing...
Article
Full-text available
The objectives of this study were to assess the efficacy of various fungicides applied as root dips, soil drenches, or foliar sprays to daylily plants grown in containers and planted in the field to manage rust caused by Puccinia hemerocallidis. Soil drenches and foliar sprays were evaluated in field experiments in Griffin, GA in 2010 and 2011. Dip...
Article
Full-text available
Fatty acid methyl ester (FAME) profiles and amplified fragment length polymorphisms (AFLPs) were evaluated as tools for identifying species of Phytophthora. Five isolates of each of Phytophthora cactorum, Phytophthora citrophthora, Phytophthora cinnamomi, Phytophthora nicotianae and Phytophthora cryptogea were subjected to both analyses to examine...
Article
Full-text available
Olson, H. A., Jeffers, S. N., Ivors, K. L., Steddom, K. C., Williams-Woodward, J. L., Mmbaga, M. T., Benson, D. M., and Hong, C. X. 2013. Diversity and mefenoxam sensitivity of Phytophthora spp. associated with the ornamental horticulture industry in the southeastern United States. Plant Dis. 97:86-92. Phytophthora isolates associated with ornament...
Conference Paper
Full-text available
Competition for fresh water resources will become more intense in coming years, forcing producers of agricultural commodities to find alternative sources of water—such as recycling irrigation runoff. Constructed wetlands have been shown to reduce or remove agrichemicals from runoff water; however, the ability to remove water-borne plant pathogens,...
Conference Paper
Full-text available
Increased water consumption by both producers of agricultural commodities and the urban community currently is causing a rise in the demand for water. Growers eventually will need to adopt water conservation and retention technology to ensure an adequate water supply for irrigation purposes. The use of constructed wetlands is an ecologically-based...
Article
The National Fire and Fire Surrogate Study was initiated to study the effects of fuel reduction treatments on forest ecosystems. Four fuel reduction treatments were applied to three sites in a southern Appalachian Mountain forest in western North Carolina: prescribed burning, mechanical fuel reduction, mechanical fuel reduction followed by prescrib...
Article
Full-text available
The effects of growth medium, incubation temperature, and mycelium age on the production of five major fatty acids by five isolates each of P. cactorum, P. citricola, P. citrophthora, P. cinnamomi, P. cryptogea, and P. nicotianae were investigated. Fatty acids were extracted from mycelia, and fatty acid methyl ester (FAME) profiles were analyzed by...
Article
Inconsistent recovery of Phytophthora cinnamomi Rands from forest soils has been documented in climates with seasonally wet and dry periods. Phytophthora cinnamomi can be recovered when soils are moist or wet but can be diffcult to recover from dry soil. Recovery may be complicated further by the physical location of P. cinnamomi in soil. Our objec...
Article
Shoot samples of four peach rootstocks that are important to the peach industry in Greece: KID I, GF305, GF677, and PR204, were inoculated with Phytophthora cactorum and Phytophthora megasperma in the field and in the glasshouse and were then evaluated with regard to susceptibility. The pathogenicity of P. cactorum and P. megasperma to peach rootst...
Article
Full-text available
GenBank, the public repository for nucleotide and protein sequences, is a critical resource for molecular biology, evolutionary biology, and ecology. While some attention has been drawn to sequence errors ([1][1]), common annotation errors also reduce the value of this database. In fact, for
Article
Fifty-one isolates of Phytophthora cinnamomi isolated from ornamental plants in South Carolina, USA, between 1995 and 2000 were characterized by sporangium morphology, mating type, sensitivity to the fungicide mefenoxam, fatty acid methyl ester (FAME) profile analysis, and amplified fragment length polymorphism (AFLP) analysis. Sporangium shapes we...
Article
Full-text available
An unidentified species of Phytophthora was isolated from irrigation water at a production nursery in Suffolk, VA in 2000 and 2001. Water samples were assayed using a filtration method (3). A similar species was recovered from soil samples collected in two mixed-hardwood forests in Fairfax County in 2002. Soil samples were air dried, remoistened, f...
Article
The recent introduction and rapid spread of rust on daylilies, caused by Puccinia hemerocallidis, suggested a need for fungicide treatments that reduce urediniospore viability on plant surfaces. Twelve fungicides in seven chemical classes were evaluated in vitro for toxicity to urediniospores of rust fungi that occur on daylily (P. hemerocallidis),...
Article
Efficacy of the yeast Rhodotorula glutinis isolate PM4 as a biological control agent against 29 isolates of Botrytis cinerea obtained from greenhouse-grown ornamentals was assessed in vitro on geranium leaf disks. Isolates of B. cinerea varied in aggressiveness in the absence of either biological or chemical controls; diameters of lesions produced...
Article
Forty-seven isolates of Phytoplithora cactorum from North America and Germany were subjected to amplified fragment length polymorphism (AFLP) analysis to investigate genetic diversity among isolates and geographical populations; 42 isolates were recovered from cultivated strawberry plants (Fragaria x ananassa), and five isolates had been recovered...
Article
Full-text available
Integrated disease management should provide the most effective means of controlling rusts on ornamental crops over time, and fungicides are an important component of an integrated rust management program. Proper timing of fungicide applications is critical for effective disease management; however, information about application timing is lacking f...
Article
Phytophthora cactorum causes crown rot of strawberry (Fragaria × ananassa) (2), a disease that has been particularly severe during the last 5 years in the southeastern United States. In the fall of 2001, strawberry plants (cv. Camarosa) in a field in Lexington County, South Carolina exhibited typical crown rot symptoms (2) 1 to 2 weeks after transp...
Article
Full-text available
ABSTRACT Phytophthora nicotianae is a common and destructive pathogen of numerous ornamental, agronomic, and horticultural crops such as tobacco, tomato, and citrus. We have developed a species-specific polymerase chain reaction (PCR) assay for rapid and accurate detection of this pathogen in irrigation water, a primary source of inoculum and an ef...
Article
Full-text available
ABSTRACT A microbioassay was developed for the discovery of compounds that inhibit Phytophthora spp. This assay uses a 96-well format for high-throughput capability and a standardized method for quantitation of initial zoospore concentrations for maximum reproducibility. Zoospore suspensions were quantifiable between 0.7 and 1.5 x 10(5) zoospores p...
Article
Fusarium root and crown rot of hosta plants grown in containers is caused primarily by Fusarium hostae. In an effort to develop an integrated strategy for managing this disease at nurseries, the effects of wounding, container mix content, watering schedule, and temperature on disease development were investigated. Plants were not wounded or were wo...
Article
Fusarium hostae sp. nov. causes Fusarium root and crown rot of container-grown hosta plants. Morphology, pathogenicity and molecular analyses based on sequences from portions of beta-tubulin and translation elongation factor 1-α genes indicate that this species is closely related to but distinct from F. redolens Wollenw. Fusarium hostae can be dist...
Article
Fusarium hostae sp. nov. causes Fusarium root and crown rot of container-grown hosta plants. Morphology, pathogenicity and molecular analyses based on sequences from portions of beta-tubulin and translation elongation factor 1-αa genes indicate that this species is closely related to but distinct from F. redolens Wollenw. Fusarium hostae can be dis...
Article
ABSTRACT Stability of phenotypes of isolates of Botrytis cinerea that were sensitive or resistant to benzimidazole and dicarboximide fungicides was examined in the absence of fungicides in laboratory and growth room experiments. Twelve greenhouse isolates of B. cinerea were subcultured on potato dextrose agar (PDA) for 20 generations and on geraniu...
Article
The effects of various natural agar media, light, and temperature on mycelium growth of and conidium production by Monilinia oxycocci were examined in the laboratory under controlled conditions. Vegetative growth and sporulation were affected differentially by these factors. Optimum vegetative growth and formation of stromata occurred on potato dex...
Article
The effects of various natural agar media, light, and temperature on mycelium growth of and conidium production by Monilinia oxycocci were examined in the laboratory under controlled conditions. Vegetative growth and sporulation were affected differentially by these factors. Optimum vegetative growth and formation of stromata occurred on potato dex...
Article
ABSTRACT A total of 56 isolates of B. cinerea collected from ornamental crops from commercial greenhouses were examined by random amplified polymorphic DNA (RAPD) fingerprint analyses. Isolates were examined as two independent sets of 35 and 36 isolates, with 15 isolates common to both sets. The isolates had four phenotypes: 17 were sensitive to tw...
Article
A previously unreported disease was observed on 11 cultivars of container-grown hosta plants at five wholesale nurseries in South Carolina between 1997 and 1999. Symptoms included leaf yellowing, plant stunting, rotting of and vascular discoloration in roots, and necrosis in the crowns. Fusarium spp. consistently were isolated from symptomatic host...
Article
In September 1999, royal ferns (Osmunda regalis L.) at a South Carolina wholesale nursery were found to be infected by foliar nematodes. Lesions were brown, vein-limited, and often fan shaped. As severity increased, affected leaflets became totally necrotic. Nematodes were extracted by excising and dicing symptomatic leaf sections and placing them...
Article
A baiting bioassay was developed to detect species of Phytophthora, i.e., those typically associated with ornamental crops, in container mixes that are used routinely in producing container-grown landscape plants. Both fresh and air-dried subsamples of container mixes were baited to improve detection of species that persist as dormant propagules. L...
Article
In 1996 and 1997, 325 isolates of Botrytis cinerea were collected from 35 commercial greenhouses growing ornamental crops in South Carolina to determine the incidence of resistance to benzimidazole and dicarboximide fungicides. Conidium germination was assessed on a defined agar medium amended with either thiophanate-methyl (a benzimidazole) or vin...
Article
The effectiveness of a new biofungicide, Bio-Save 11, based on a strain of Pseudomonas syringae (ESC-11 = L-59-66) and formulated as a 10% wettable powder was evaluated and compared to thiabendazole and fresh cells of the bacterium using two apple (Malus X domestica Borkh.) cultivars in each of two seasons. The effectiveness of a 10% wettable powde...
Article
In trials over a 6-yr period, roots of dormant MM.106 apple (Malus domestica) rootstocks were soaked in aqueous fungicide suspensions before planting to reduce the incidence of naturally occurring inoculum of Phytophthora cactorum and P. cambivora, causal agents of Phytophthora crown rot. Initially, roots were soaked for 10 min or 1 hr in 1,000 mg/...
Article
Native populations of Trichoderma spp in soils associated with apple trees in Wisconsin were quantified and the diversity of species present was characterized. In all, 20 soils were sampled from four geographical regions of Wisconsin: 17 from around apple trees, two from woodlands immediately downhill from apple orchards and one from a virgin white...
Article
In 1987 and 1988, leaves and fruit were collected at 2-wk intervals for 20 wk from replicated plots at two commercial cranberry (cultivar Searles) marshes in central Wisconsin. Leaves were collected from budbreak, and berries were collected from 8 and 6 wk after budbreak in 1987 and 1988, respectively, until harvest. Beginning during bloom, captafo...
Article
Over a 3-yr period (1987-1989), 11 fungicides were evaluated for efficacy in managing cottonball in a commercial cranberry bed heavily infested with Monilinia oxycocci. Three applications, beginning at budbreak, were made to control primary infection of shoots by ascospores, and two applications were made during bloom to control fruit rot caused by...
Article
Captafol, chlorothalonil, and mancozeb were applied to the same plots, which were established in commercial cranberry (cv. Searles) beds at two locations in central Wisconsin, for three consecutive years to manage postharvest storage rots of fresh fruit. Applications were initiated progressively earlier each year in relation to bloom (late bloom in...
Article
Full-text available
Methods for detecting Phytophthora ramorum and other Phytophthora species with rhododendron leaf baits were pilot tested in high-risk watersheds in 11 states for the purpose of recommending a national survey protocol. Ninety streams, including 14 draining P. ramorum-endemic areas, yielded 587 baiting chances. Molecular diagnostic assays detected th...
Article
Species of Rhizoctonia induce important diseases of tall fescue (Festuca arundinacea Schreb.) in the south-eastern United States. There is little information on thefrequencies of infection levels of tall fescue by anastomosis groups (AG) of R. solani Kuhn or other Rhizoctonia species. In this study, leaf and crown tissues from two tall fescue culti...
Article
To evaluate the number of stream sample sites needed to effectively survey a given stream network for species of Phytophthora, two stream networks, Davidson River and Cathey's Creek, in western North Carolina (USA) were studied. One-litre water samples were collected from the terminal drainage points and most of the tributaries in each stream netwo...
Conference Paper
The restoration of the American Chestnut (Castanea dentata) requires the production of genotypes that are resistant to the Chestnut blight, Cryphonectria parasitica. An additional source of Chestnut death in the southern range of the United States is ink disease, Phytophthora cinnamomi. QTL mapping has yielded regions of interest in the Chinese Che...
Article
Photocopy of typescript. Thesis (M.S.)--Cornell University, May, 1980. Includes bibliographies.

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